A congressional ethics report has recommended further investigations into allegations Rep. Tim Bishop violated House rules and federal law last year, saying there was a “substantial reason” to believe Mr. Bishop broke federal campaign finance rules.

The report, released Wednesday by the Office of Congressional Ethics, found there was reason to believe that Mr. Bishop helped a constituent get permits to hold a fireworks show, then had his staff ask the man for a campaign contribution as a quid pro quo.

The probe also found that Mr. Bishop’s campaign committee may have misreported a $5,000 contribution from the constituent’s company that broke the $2,500 per election limit.

“There is a substantial reason to believe that Representative Bishop sought a campaign contribution because of or in connection with an official act in violation of House rules, standards of conduct, and federal law,” according to the 117-page report.

The Office of Congressional Ethics has advised the House Committee on Ethics to further review the allegations.

Mr. Bishop has denied the allegations; his lawyers filed a response to the probe that called the allegations “deeply flawed.”

“The report released today confirms that the allegations made against me last summer were politically orchestrated and I am confident that the ongoing review of this matter will show that I acted in good faith to assist a constituent in need,” Mr. Bishop said in a statement.

Mr. Bishop allegedly helped Eric Semler, a Sagaponack hedge fund manager, get the necessary permits to hold a fireworks display for his son’s bar mitzvah on May 26, 2012, according to email evidence in the report.

After the permits were believed to be cleared, Mr. Bishop wrote an email to a close friend, Robert Sillerman, asking him to ask Mr. Semler for a contribution.

“We are all set with Eric Semler,” the email from Mr. Bishop detailed in the report states. “Hey, would you be willing to reach out to him to ask for a contribution? If he donates before June 26, he and his wife can each do 5 large – if it is after June 26, they can each do a max of 2500.”

Mr. Bishop’s response says that Mr. Semler was under no pressure to give a contribution, notes that Mr. Bishop did not personally contact him about a donation, and noted that Mr. Semler said in an interview in the report that he made the contribution because Rep. Bishop is a “stellar politician.”

The report also states that Mr. Bishops campaign misreported a $5,000 contribution from Mr. Semler’s company TCS Capital Management LLC as being two $2,500 from Mr. Semler and his wife. The campaign also reported the date of the contribution as June 26, not July 9 when the contribution was actually received, the report states.

Mr. Bishop’s attorneys said in his response that while the finding allege the campaign misreported the contribution, the re-election campaign “took reasonable steps” including hiring a FEC compliance official to report the contribution correctly.

House Committee on Ethics said in a statement that it will “continue to gather information necessary to complete its review” of the allegations against Mr. Bishop.